The present invention relates to a wiring harness holding device for a wiring harness which is laid out in such a manner as to extend between a stationary structure such as a vehicle body of a motor vehicle and a movable structure such as a sliding seat or sliding door which slides relative to the vehicle body and more particularly to a wiring harness holding device for absorbing an excess length of the wiring harness which is produced in association with the sliding of the movable structure.
Among automotive components, sliding seats and sliding doors are components which slide largely relative to the vehicle body. When attempting to install electric equipment at the sliding seat or sliding door, a wiring harness needs to be laid out in such a manner as to extend between the electric equipment and the vehicle body, and when this is actually carried out, there has been caused a difficulty in accommodating the wiring harness.
For example, since a sliding seat used on a currently popular minivan slides largely, an excess length is generated in a wiring harness 6 in association with the sliding movement of the sliding seat 5 as shown in FIG. 14, being likely to cause a problem that the occupant is caught at his or her leg by the wiring harness 6 which is loosened due to the excess length so produced.
To cope with this problem, there has been proposed a wiring harness holding device for enabling the extension and contraction of a wiring harness laid out between a sliding seat and a vehicle body according to the sliding movement of the sliding seat (for example, refer to JP-A-10-112922).
A wiring harness holding device disclosed in JP-A-10-112922 includes, as shown in FIG. 15, a protector 1 which is provided in parallel with a sliding direction of the sliding seat along a longitudinal direction thereof, a stationary side connector 2 which is provided at a front end of the protector 1 and a slider 3 which is brought into engagement and connection with the protector 1 and the sliding seat, respectively, in such a manner as to slide in the longitudinal direction of the protector 1.
A wiring harness 4 is accommodated within the protector 1 while being folded back substantially into a U-shape and is connected to the stationary side connector 2 at one end and to the slider 3 at the other end thereof. The wiring harness 4 extends and contracts within the protector 1 in association with the sliding of the slider 3 while moving the folded back portion back and forth along the sliding direction of the slider 3, whereby an excess length of the wiring harness 4 is absorbed which is produced in association with the sliding of the slider 3.
In the wiring harness holding device disclosed in JP-A-10-112922, the stationary side connector 2 and the slider 3 are aligned in the sliding direction of the slider 3, and the wiring harness 4 extending from the stationary side connector 2 is firstly allowed to so extend to the rear of the slider 3 and is then folded back in a substantially U-shaped fashion so as to be connected to the slider 3 from the rear thereof. In other words, for it to be caused to exit from the slider 3 towards the stationary side connector 2, the wiring harness 4 is firstly caused to extend to the rear of the slider 3.
Then, in order to avoid a damage at the folded back portion of the wiring harness 4 due to bending, an excess length L is secured at the rear of the slider 3 for keeping the radius of curvature at the folded back portion to a permissible value or greater in such a state that the wiring harness 4 is extended to its maximum length as shown in FIG. 16.
It appears that this causes a disadvantage in reducing the size of the wiring harness holding device. Namely, in a wiring harness of a large diameter such as one in which a general electric wire (an earth wire) needing a current capacity is provided in parallel, the permissible radius of curvature tends to be increased, and since the excess length L also needs to be set large in association with the increase in the radius of curvature, this construction tends to be a disadvantage in making the wiring harness holding device smaller in its size. In addition, the excess length is designed to meet the sliding stroke of the sliding seat and the radius of curvature of the wiring harness exclusively for each model, and this causes a problem that this wiring harness holding device is inferior with respect to general-purpose properties.